scholarly journals A matched filter approach for blind joint detection of galaxy clusters in X-ray and SZ surveys

2018 ◽  
Vol 614 ◽  
pp. A82 ◽  
Author(s):  
P. Tarrío ◽  
J.-B. Melin ◽  
M. Arnaud
Keyword(s):  
Galaxy Clusters ◽  
Matched Filter ◽  
Detection Efficiency ◽  
Blind Detection ◽  
Joint Detection ◽  
Ionized Gas ◽  
X Ray ◽  
Sky Survey ◽  
Filter Approach ◽  
Using Data

The combination of X-ray and Sunyaev–Zeldovich (SZ) observations can potentially improve the cluster detection efficiency, when compared to using only one of these probes, since both probe the same medium, the hot ionized gas of the intra-cluster medium. We present a method based on matched multifrequency filters (MMF) for detecting galaxy clusters from SZ and X-ray surveys. This method builds on a previously proposed joint X-ray–SZ extraction method and allows the blind detection of clusters, that is finding new clusters without knowing their position, size, or redshift, by searching on SZ and X-ray maps simultaneously. The proposed method is tested using data from the ROSAT all-sky survey and from the Planck survey. The evaluation is done by comparison with existing cluster catalogues in the area of the sky covered by the deep SPT survey. Thanks to the addition of the X-ray information, the joint detection method is able to achieve simultaneously better purity, better detection efficiency, and better position accuracy than its predecessor Planck MMF, which is based on SZ maps alone. For a purity of 85%, the X-ray–SZ method detects 141 confirmed clusters in the SPT region; to detect the same number of confirmed clusters with Planck MMF, we would need to decrease its purity to 70%. We provide a catalogue of 225 sources selected by the proposed method in the SPT footprint, with masses ranging between 0.7 and 14.5 ×1014 M⊙ and redshifts between 0.01 and 1.2.

scholarly journals Joint signal extraction from galaxy clusters in X-ray and SZ surveys: A matched-filter approach

2016 ◽  
Vol 591 ◽  
pp. A39 ◽  
Author(s):  
P. Tarrío ◽  
J.-B. Melin ◽  
M. Arnaud ◽  
G. W. Pratt
Keyword(s):  
Galaxy Clusters ◽  
Matched Filter ◽  
Signal Extraction ◽  
X Ray ◽  
Filter Approach

scholarly journals Redshift measurement through star formation

2019 ◽  
Vol 629 ◽  
pp. A7
Author(s):  
Mikkel O. Lindholmer ◽  
Kevin A. Pimbblet
Keyword(s):  
Star Formation ◽  
Galaxy Clusters ◽  
Main Sequence ◽  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
X Ray ◽  
Star Forming ◽  
Sky Survey ◽  
The Galaxy ◽  
Galaxy Population

In this work we use the property that, on average, star formation rate increases with redshift for objects with the same mass – the so called galaxy main sequence – to measure the redshift of galaxy clusters. We use the fact that the general galaxy population forms both a quenched and a star-forming sequence, and we locate these ridges in the SFR–M⋆ plane with galaxies taken from the Sloan Digital Sky Survey in discrete redshift bins. We fitted the evolution of the galaxy main sequence with redshift using a new method and then subsequently apply our method to a suite of X-ray selected galaxy clusters in an attempt to create a new distance measurement to clusters based on their galaxy main sequence. We demonstrate that although it is possible in several galaxy clusters to measure the main sequences, the derived distance and redshift from our galaxy main sequence fitting technique has an accuracy of σz = ±0.017 ⋅ (z + 1) and is only accurate up to z ≈ 0.2.

scholarly journals A systematic study of X-ray substructure of galaxy clusters detected in the ROSAT All-Sky Survey

2001 ◽  
Vol 378 (2) ◽  
pp. 408-427 ◽  
Author(s):  
P. Schuecker ◽  
H. Böhringer ◽  
T. H. Reiprich ◽  
L. Feretti
Keyword(s):  
Galaxy Clusters ◽  
Systematic Study ◽  
X Ray ◽  
Sky Survey

scholarly journals Synthetic simulations of the extragalactic sky seen by eROSITA

2018 ◽  
Vol 617 ◽  
pp. A92 ◽  
Author(s):  
N. Clerc ◽  
M. E. Ramos-Ceja ◽  
J. Ridl ◽  
G. Lamer ◽  
H. Brunner ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Detection Efficiency ◽  
Photon Emission ◽  
Cosmological Parameters ◽  
Galaxy Cluster ◽  
Selection Function ◽  
Selection Effects ◽  
Source Detection ◽  
Telescope Array ◽  
X Ray

Context. Studies of galaxy clusters provide stringent constraints on models of structure formation. Provided that selection effects are under control, large X-ray surveys are well suited to derive cosmological parameters, in particular those governing the dark energy equation of state. Aims. We forecast the capabilities of the all-sky eROSITA (extended ROentgen Survey with an Imaging Telescope Array) survey to be achieved by the early 2020s. We bring special attention to modelling the entire chain from photon emission to source detection and cataloguing. Methods. The selection function of galaxy clusters for the upcoming eROSITA mission is investigated by means of extensive and dedicated Monte-Carlo simulations. Employing a combination of accurate instrument characterisation and a state-of-the-art source detection technique, we determine a cluster detection efficiency based on the cluster fluxes and sizes. Results. Using this eROSITA cluster selection function, we find that eROSITA will detect a total of approximately 105 clusters in the extra-galactic sky. This number of clusters will allow eROSITA to put stringent constraints on cosmological models. We show that incomplete assumptions on selection effects, such as neglecting the distribution of cluster sizes, induce a bias in the derived value of cosmological parameters. Conclusions. Synthetic simulations of the eROSITA sky capture the essential characteristics impacting the next-generation galaxy cluster surveys and they highlight parameters requiring tight monitoring in order to avoid biases in cosmological analyses.

scholarly journals X-Ray Selected EUV Galaxies: A Quest for the Faintest Extragalactic EUV Sources

1996 ◽  
Vol 152 ◽  
pp. 69-73
Author(s):  
Antonella Fruscione
Keyword(s):  
Extreme Ultraviolet ◽  
X Ray ◽  
The Public ◽  
Euv Emission ◽  
Sky Survey ◽  
Using Data ◽  
First Time

Using data from the public archive of the Extreme Ultraviolet Explorer (EUVE) all-sky survey, we have systematically searched for extreme ultraviolet (EUV) emission (58-174 Å, 0.07-0.21 keV) around approximately 2500 distinct positions in the sky corresponding to known X-ray emitting extragalactic sources. We find that 20 X-ray galaxies are EUV bright and were detected with significance above 4 σ during the EUVE survey: 8 are reported here for the first time (MS 0037.7−0156, Mrk 142, M 65, EXO 1128.1+6908, M 87, Mrk 507, PKS 2005–489 and 1H 2351−315.A). 68 additional galaxies are detected with a lower significance (3 < σ < 4), but the list is affected by a high percentage of spurious sources.

scholarly journals Mass calibration of the CODEX cluster sample using SPIDERS spectroscopy – I. The richness–mass relation

2019 ◽  
Vol 486 (2) ◽  
pp. 1594-1607 ◽  
Author(s):  
R Capasso ◽  
J J Mohr ◽  
A Saro ◽  
A Biviano ◽  
N Clerc ◽  
...  
Keyword(s):  
Matched Filter ◽  
Mass Relation ◽  
Scaling Relation ◽  
Cluster Galaxy ◽  
X Ray ◽  
Mass Scaling ◽  
Sky Survey ◽  
The Impact ◽  
Parameter Constraints ◽  
Red Sequence

Abstract We use galaxy dynamical information to calibrate the richness–mass scaling relation of a sample of 428 galaxy clusters that are members of the CODEX sample with redshifts up to z ∼ 0.7. These clusters were X-ray selected using the ROSAT All-Sky Survey (RASS) and then cross-matched to associated systems in the redMaPPer (the red sequence Matched-filter Probabilistic Percolation) catalogue from the Sloan Digital Sky Survey. The spectroscopic sample we analyse was obtained in the SPIDERS program and contains ∼7800 red member galaxies. Adopting NFW mass and galaxy density profiles and a broad range of orbital anisotropy profiles, we use the Jeans equation to calculate halo masses. Modelling the scaling relation as $\lambda \propto \text{A}_{\lambda } {M_{\text{200c}}}^{\text{B}_{\lambda }} ({1+z})^{\gamma _{\lambda }}$, we find the parameter constraints $\text{A}_{\lambda }=38.6^{+3.1}_{-4.1}\pm 3.9$, $\text{B}_{\lambda }=0.99^{+0.06}_{-0.07}\pm 0.04$, and $\gamma _{\lambda }=-1.13^{+0.32}_{-0.34}\pm 0.49$, where we present systematic uncertainties as a second component. We find good agreement with previously published mass trends with the exception of those from stacked weak lensing analyses. We note that although the lensing analyses failed to account for the Eddington bias, this is not enough to explain the differences. We suggest that differences in the levels of contamination between pure redMaPPer and RASS + redMaPPer samples could well contribute to these differences. The redshift trend we measure is more negative than but statistically consistent with previous results. We suggest that our measured redshift trend reflects a change in the cluster galaxy red sequence (RS) fraction with redshift, noting that the trend we measure is consistent with but somewhat stronger than an independently measured redshift trend in the RS fraction. We also examine the impact of a plausible model of correlated scatter in X-ray luminosity and optical richness, showing it has negligible impact on our results.

scholarly journals The impact of disturbed galaxy clusters on the kinematics of active galactic nuclei

2020 ◽  
Vol 499 (3) ◽  
pp. 3792-3805
Author(s):  
Lawrence E Bilton ◽  
Kevin A Pimbblet ◽  
Yjan A Gordon
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Clusters ◽  
Velocity Dispersion ◽  
Signal To Noise Ratio ◽  
Galactic Nuclei ◽  
Sloan Digital Sky Survey ◽  
X Ray ◽  
Cluster Galaxies ◽  
Sky Survey ◽  
The Impact

ABSTRACT We produce a kinematic analysis of AGN-hosting cluster galaxies from a sample of 33 galaxy clusters selected using the X-ray Clusters Database (BAX) and populated with galaxies from the Sloan Digital Sky Survey Data Release 8. The 33 galaxy clusters are delimited by their relative intensity of member galaxy substructuring as a proxy to core merging to derive two smaller sub-samples of 8 dynamically active (merging) and 25 dynamically relaxed (non-merging) states. The AGN were selected for each cluster sub-sample by employing the WHAN diagram to the strict criteria of log10([N ii]/Hα) ≥ −0.32 and EWHα ≥ 6 Å, providing pools of 70 mergings and 225 non-merging AGN sub-populations. By co-adding the clusters to their respective dynamical states to improve the signal-to-noise ratio of our AGN sub-populations we find that merging galaxy clusters on average host kinematically active AGN between 0–1.5r200 as r200 → 0, where their velocity dispersion profile (VDP) presents a significant deviation from the non-AGN sub-population VDP by ≳3σ. This result is indicative that the AGN-hosting cluster galaxies have recently coalesced on to a common potential. Further analysis of the composite distributions illustrates non-merging AGN-hosting sub-populations have, on average, already been accreted and predominantly lie within backsplash regions of the projected phase-space. This suggests merging cluster dynamical states hold relatively younger AGN sub-populations kinematically compared with those found in non-merging cluster dynamical states.

scholarly journals Catalog of X-ray-selected extended galaxy clusters from the ROSAT All-Sky Survey (RXGCC)

2021 ◽  
Author(s):  
W. Xu ◽  
M. E. Ramos-Ceja ◽  
F. Pacaud ◽  
T. H. Reiprich ◽  
T. Erben
Keyword(s):  
Galaxy Clusters ◽  
X Ray ◽  
Sky Survey

scholarly journals Recent X-Ray Observations of Seyferts and Emission-Line Galaxies

1980 ◽  
Vol 5 ◽  
pp. 641-651 ◽  
Author(s):  
R. E. Griffiths
Keyword(s):  
Average Error ◽  
X Ray ◽  
The Past ◽  
Sky Survey ◽  
Emission Line Galaxies ◽  
Modulation Collimator ◽  
Using Data ◽  
Seyfert Nucleus ◽  
Einstein Observatory

It has been just a few years since Type 1 Seyferts were established as a class of X-ray sources with luminosities in the range 1042 - 1045 ergs s-1 by Elvis et al. (1978) using data from the sky survey instrument on Ariel V, and by Tananbaum et al. (1978) using data from UHURU.The average error-box sizes for X-ray sources identified with Type 1 Seyferts in the 2A catalog (Cooke et al. 1978) is ˜ 0.4 sq. degrees, and ˜ 1.0 sq. degrees for those in the 4U catalog (Forman et al. 1978). Improvement in these positions has been made over the past two years by the modulation collimators on board the satellites SAS-3 and HEAO-1. In particular, the HEAO-1 scanning modulation collimator has been used to position a total of 20 X-ray sources, confirming the identification in each case, with the possible exception of Mkn 279 (Dower et al. 1979, Griffiths et al. 1979a). Of the 37 X-ray sources which were discovered prior to the launch of the Einstein Observatory and which have been associated with Type 1 Seyferts, 21 have been positioned to ˜ 1 arc minute, representing an improvement by factors of ˜ 20 to 100 over the previous 2A and 4U error box sizes. Some examples of the error boxes and identifications confirmed with the HEAO-1 scanning modulation collimator are shown in figs. 1 and 2. In fig. 1 both NGC 7213 (Philips 1979) and MCG - 2 - 58 - 22 (Ward et al. 1978) were discovered to be Seyferts by optical spectroscopy of candidate objects in the error regions of the corresponding X-ray sources. NGC 7213 is a Seyfert nucleus in a galaxy of Type SO (Philips 1979). In fig. 2, NGC 931 was likewise discovered to be a Seyfert as a result of its X-ray emission (Ward and Wilson 1978).

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